KANSAS CITY, Mo. — Dorian O’Daniel and Breeland Speaks, two of the newest drafted rookies for the Kansas City Chiefs, arrived in town earlier this week and started learning about each other as temporary hotel roommates.

They talked about their backgrounds. They talked about football. They talked about their new Chiefs’ playbook. Then they started envisioning how they could be productive together.

Before the Chiefs’ rookie minicamp started Saturday, the five drafted defensive rookies — O’Daniel, Speaks, Derrick Nnadi, Armani Watts and Tremon Smith — all began to understand how unique their shared NFL experience could be. When the NFL Draft ends, it’s rare to see a team select almost all of its prospects on one side of the ball. For the first time in the franchise’s history, the Chiefs only selected prospects who played on defense during their collegiate careers. Five of the six rookies, excluding Kahlil McKenzie, are hoping to help rebuild the...